What are these small black ants suddenly swarming in my house? Anna, Queensland, Australia

I stumbled across your very interesting blog whilst searching for an answer about ants.

We live in the sub-tropics (Queensland, Australia) and just over a week ago experienced severe wet weather (flash flooding) due to an ex-cyclone passing over us. This was after an extended period of dry weather in a hot Summer. We have had a steady stream of various ants come in due to the weather, mostly heading for the kitchen. This is quite normal for us and has been managed mainly by keeping minimal accessible crumbs etc.

The unusual ant activity we've had is in the last couple of days. One night we suddenly realised that there were clumps of tiny black ants all over the house. There were thousands of them in the laundry, on the top of the wall and cornice - not many down near the water sources at all. There were also about 6 big clusters of them located on cornices throughout our living room and hallway - far from any food source and/or water. The next day another cluster appeared on the door frame of our bedroom en suite - these ones were near some artwork and some were feasting on the glue used in it, but most were in clumps on the doorframe. I took some pictures and have attached them.

Ants1 is to give you a reference point for size and the shapes of all the small clusters these ants are forming - these are very small ants compared to most others we get locally.
Ants2 is a closer shot - when I was later looking at the photos I noticed that the ants appeared to be clustered around some sort of larvae or white-fleshed ant? I suppose this is why they are clumping, but am wondering what the white things are. I am hoping it is not termites! I am also curious as to why these ants all suddenly appeared in such unlikely places (and so many times) particularly given that it had been about a week since the wet weather. I would also like to know what we can do to try and discourage them from invading our house in such a huge and sudden manner.

I've done some searching on ant identification pages etc. and the closest ant I can come up with that they may be is the "black house ant". Although I am not sure they have the right number of joins in their body.

Any answers to my questions would be much appreciated!

I can send a bigger sized picture if you require it, just let me know if you do need it. I just didn't want to unnecessarily overload your inbox with a large sized file.

Thank you,

Anna.

Dear Anna,

Thanks for the question and the pictures!

First off, these are definitely not termites. Note the "elbowed" antennae and distinct rear part of the body (called the "gaster" in ant literature).

These ants probably belong to the genus Technomyrmex. They're very common in forests in tropical Southeast Asia and Australia. I used to work on a small group of islands called Palau, and there were parts of the forest where it seemed like nearly every tree had this density of Technomyrmex on them. Although it's tough to say for certain, it's likely that these ants belong to a group of very similar-looking species that would have all been identified as Technomyrmex albipes a few years ago, but have since been shown to belong to several distinct species, including T. difficilis (guess why it has that name!). Here are some close-up pictures of the ants I think you have (although this this ant is fairly widespread, these pictures were actually taken in Queensland). In your region, many common household ants can be identified using a key developed by Eli Sarnat for the Pacific Invasive Ants program out of New Zealand (assuming you have a good microscope). For more complete information on ants in your area, check out our Queensland section on AntWeb, and Steve Shattuck's Ants Down Under.

We've written a few posts about getting rid of ants in and around your home (for example: here, here, here, and here), but in your case, one of the more important actions might be keeping vegetation from touching your house. I've actually seen a house in Palau that was entirely on concrete stilts, and each stilt rested on a concrete block that had a small moat of water in it - this is essentially the house-level equivalent to putting the legs of your kitchen table in tuna cans filled with water to prevent ants from climbing up. However, the house got electricity from an above-ground wire, and there was a steady stream of Technomyrmex coming in on that wire all the time! So....I guess there's only so much you can do!

Hope this helps, and good luck!
best,
Jesse Czekanski-Moir & the AntAsk Team